Previous researches have indicated the relevance between segmental duration and syntax information, but the usefulness of syntax features have not been thoroughly studied for predicting segmental duration. In this paper, we design two sets of syntax features to improve Mandarin phone and pause duration prediction respectively. Instead of using manually extracted syntacx information as previous researches do, we acquire these syntax features from an automatic Chinese syntax parser. Results show that even though the automatically extracted syntax information has limited precision; it could still improve Mandarin segmental duration prediction.